The present invention relates generally to a flange for hollow articles, and more specifically to a flange attached to both ends of a hollow article such as a core paper tube rod around which a long length of photographic paper or photosensitive film is wound.
For packaging and transportation of long lengths of photosensitive materials such as photographic paper, and photosensitive film, and attachment of them to machines, they are usually wound around a hollow core rod. For protection of the roll of photosensitive material, shielding it from light and ease of its handling, a disk-like flange is attached to a hollow paper tube with the photosensitive material wound around it.
Some methods for attaching such flanges to hollow core rods have so far been proposed in JU-A 1-38582, JU-B 1-38582, JP-A 9-211800, etc. JU-A 1-38582 discloses to couple a flange to a hollow core rod by use of a bonding agent. JU-B 6-31465 discloses a flange having an inserting member at its center, which is to be inserted through a hollow in a core rod. The inserting member is provided therearound with projections which are to be in engagement with the flange. JP-A 9-211800 discloses that a threaded shaft is axially inserted through a hollow in a core rod for connection and fixation to flanges at both ends thereof.
Such flanges are usually formed of plastics. Once a roll of photosensitive material has been used up, a paper tube with flanges attached thereto is discarded. However, the plastic flanges must be discarded while they are separated from the paper tube.
The flanges disclosed in JU-A 1-38582 are bonded to the paper tube, and it is not easy to separate the flanges from the paper tube. In the flanges disclosed in JU-B 6-31465, too, it is not easy to separate them from the paper tube because the projections are engaged in the paper tube. A special tool is needed for removal of the threaded shaft disclosed in JP-A 9-211800 from the paper tube.
Thus, the prime purpose of the prior art methods is to ensure the coupling of flanges to paper tubes, etc. In other words, ease of flange removal and the ability of flanges to be discarded are a matter of no interest, and so users suffer inconvenience.